Typical Concrete Damages:
Corrosion of Rebar: Rebar is protected by the oxide layer in alkaline concrete. Carbon dioxide reduces concrete's alkalinity from outside to inside by formation of calcium carbonate. At a pH <9.5 the passivated layer fails and the surface corrosion of rebar begins.
Chloride Induced Corrosion: Chloride sources are deicing salts or sea water. Chlorides penetrate into concrete with water acting as a transporter. Upon water seepage, pitting, spalling, cracking and corrosion starts.
ASR (Alkali Silica Reaction): ASR is the reaction between reactive aggregates and alkalinity catalyzed by alkali (deicing salts). This can result in discoloration, micro cracks, and break up.
- Salt Blooming & Leaching: Dissolved sulfates chemically attack concrete which leads to pressure build up and cracks. Pure water can leach out calcium slats and leave the surface strongly weathered. Pollutants can penetrate easily into the open pore structure.
All of the above damages require water either as a transporter or reactor. Since they all require water, hydrophobic concrete sealers will prevent damages such as: chloride induced corrosion of rebar, carbonation, freeze-thaw damage, alkali silica reaction and gasous pollutants.